InteBac: An integrated bacterial and baculovirus expression vector suite.

The successful production of recombinant protein for biochemical, biophysical, and structural biological studies critically depends on the correct expression organism. Currently, the most commonly used expression organisms for structural studies are Escherichia coli (70% of all PDB structures) and the baculovirus/ insect cell expression system (5% of all PDB structures). While insect cell expression is frequently successful for large eukaryotic proteins, it is relatively expensive and time-consuming compared to E. coli expression. Frequently the decision to carry out a baculovirus project means restarting cloning from scratch. Here we describe an integrated system that allows simultaneous cloning into E. coli and baculovirus expression vectors using the same PCR products. The system offers a flexible array of N- and C-terminal affinity, solubilization and utility tags, and the speed allows expression screening to be completed in E. coli, before carrying out time and cost-intensive experiments in baculovirus. Importantly, we describe a means of rapidly generating polycistronic bacterial constructs based on the hugely successful biGBac system, making InteBac of particular interest for researchers working on recombinant protein complexes.